| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
SKELETAL MUSCLE AND EXERCISE |
1 Clinique Romande de Réadaptation SUVA Care2Department of Radiology, Sion Hospital, CH-1951 Sion, Switzerland
Skeletal muscle size is tightly regulated by the synergy between anabolic and catabolic signalling pathways which, in humans, have not been well characterized. Akt has been suggested to play a pivotal role in the regulation of skeletal muscle hypertrophy and atrophy in rodents and cells. Here we measured the amount of phospho-Akt and several of its downstream anabolic targets (glycogen synthase kinase-3ß (GSK-3ß), mTOR, p70s6k and 4E-BP1) and catabolic targets (Foxo1, Foxo3, atrogin-1 and MuRF1). All measurements were performed in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. Following resistance training a muscle hypertrophy (
10%) and an increase in phospho-Akt, phospho-GSK-3ß and phospho-mTOR protein content were observed. This was paralleled by a decrease in Foxo1 nuclear protein content. Following the de-training period a muscle atrophy (5%), relative to the post-training muscle size, a decrease in phospho-Akt and GSK-3ß and an increase in Foxo1 were observed. Atrogin-1 and MuRF1 increased after the hypertrophy and decreased after the atrophy phases. We demonstrate, for the first time in human skeletal muscle, that the regulation of Akt and its downstream signalling pathways GSK-3ß, mTOR and Foxo1 are associated with both the skeletal muscle hypertrophy and atrophy processes.
(Received 6 July 2006;
accepted after revision 14 August 2006;
first published online 17 August 2006)
Corresponding author A. P. Russell: School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway 3125, Australia. Email: aaron.russell{at}deakin.edu.au
This article has been cited by other articles:
|
|
 |
|
  S. B. Wilkinson, S. M. Phillips, P. J. Atherton, R. Patel, K. E. Yarasheski, M. A. Tarnopolsky, and M. J. Rennie Differential effects of resistance and endurance exercise in the fed state on signalling molecule phosphorylation and protein synthesis in human muscle J. Physiol., August 1, 2008; 586(15): 3701 - 3717. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Nedergaard, K. Vissing, K. Overgaard, M. Kjaer, and P. Schjerling Expression patterns of atrogenic and ubiquitin proteasome component genes with exercise: effect of different loading patterns and repeated exercise bouts J Appl Physiol, November 1, 2007; 103(5): 1513 - 1522. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. I. Lewis, M. Fournier, T. W. Storer, S. Bhasin, J. Porszasz, S.-G. Ren, X. Da, and R. Casaburi Skeletal muscle adaptations to testosterone and resistance training in men with COPD J Appl Physiol, October 1, 2007; 103(4): 1299 - 1310. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Constantin, D. Constantin-Teodosiu, R. Layfield, K. Tsintzas, A. J. Bennett, and P. L. Greenhaff PPAR{delta} agonism induces a change in fuel metabolism and activation of an atrophy programme, but does not impair mitochondrial function in rat skeletal muscle J. Physiol., August 15, 2007; 583(1): 381 - 390. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Doucet, A. P. Russell, B. Leger, R. Debigare, D. R. Joanisse, M.-A. Caron, P. LeBlanc, and F. Maltais Muscle Atrophy and Hypertrophy Signaling in Patients with Chronic Obstructive Pulmonary Disease Am. J. Respir. Crit. Care Med., August 1, 2007; 176(3): 261 - 269. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
